Gardeners can grow bigger, juicier tomatoes this summer by performing a simple pruning task in June, according to greenhouse experts at Juliana. The technique, known as truss pruning, redirects the plant's energy into fewer fruits, resulting in larger yields.
What Is Truss Pruning?
Truss pruning involves removing some of the fruit on a truss—the cluster where tomatoes develop—to allow the remaining fruit to grow larger. The Juliana team explained: "To maximise the size of your tomatoes, consider truss pruning. This is especially important on larger, beefsteak tomatoes, where the weight of developing fruit can damage the plants."
The Royal Horticultural Society (RHS) notes that cordon or indeterminate tomatoes, which grow tall and require supports like wooden stakes, benefit from truss pruning. These varieties are common in UK gardens and greenhouses.
When to Prune Tomatoes in June
Tomatoes grown indoors, whether in a kitchen or greenhouse, should be truss-pruned once they have produced seven fruit trusses. For those cultivated outdoors, consider pruning when the plant reaches four trusses. Pruning in June, when plants typically begin setting fruit, ensures the plant prioritises the right trusses before summer's peak ripening period.
In the UK, tomatoes start to ripen from mid-summer onwards, though timing differs depending on variety, weather conditions, and fruit size. In a greenhouse, tomatoes typically fruit from June through to October.
How to Prune Tomatoes for Bigger Fruits
According to the greenhouse specialists, gardeners should aim to keep roughly four to six tomatoes per truss on indoor tomato plants. They advised: "Remove the smallest or misshapen fruits, allowing the plant to concentrate its energy on developing fewer, but larger, fruits. Regularly check your plants and prune as needed throughout June."
Think of it as helping your tomato plant focus its resources: instead of nurturing eight or ten smaller fruits, it channels more sugar, water, and nutrients towards just four or five, yielding bigger, more flavoursome tomatoes. This simple technique takes mere seconds per truss and can significantly improve harvest quality.
